Studies on the Effect of High Energy Ball Milling On the Structural, Electrical and Magnetic Properties of Some Normal Spinets in the Ultrafine Regime

The present work is an attempt to understand the characteristics of high energy ball milling on the structural, electrical and magnetic properties of some normal spinets in the ultra fine regime, Magnetism and magnetic materials have been a fascinating subject for the mankind ever since the discovery of lodestone. Since then, man has been applying this principle of magnetism to build devices for various applications. Magnetism can be classified broadly into five categories. They are diamagnetic, paramagnetic, ferromagnetic antiferromagnetic and ferrimagnetic. Of these, ferro and ferri magnetic materials assume great commercial importance due to their unique properties like appropriate magnetic characteristics, high resistivity and low eddy current losses. The emergence of nanoscience and nanotechnology during the last decade had its impact in the field of magnetism and magnetic materials too. Now, it is common knowledge that materials synthesized in the nanoregime exhibit novel and superlative properties with respect to their coarser sized counterparts in the micron regime. These studies reveal that dielectric properties can be varied appreciably by high-energy ball milling in nanosized zinc ferrites produced by coprecipitation method. A semi conducting behaviour was observed in these materials with the Oxygen vacancies acting as the main charge carrier for conduction, which was produced at the time of coprecipitation and milling. Thus through this study, it was possible to successfully investigate the finite size effects on the structural, electrical and magnetic properties of normal spinels in the ultra fine regime

STUDIES ON SCATTERING AND QUASI-NORMAL MODES IN BLACK HOLE SPACE-TIMES

The question of stability of black hole was first studied by Regge and Wheeler who investigated linear perturbations of the exterior Schwarzschild spacetime. Further work on this problem led to the study of quasi-normal modes which is believed as a characteristic sound of black holes. Quasi-normal modes (QNMs) describe the damped oscillations under perturbations in the surrounding geometry of a black hole with frequencies and damping times of oscillations entirely fixed by the black hole parameters.In the present work we study the influence of cosmic string on the QNMs of various black hole background spacetimes which are perturbed by a massless Dirac field.

Meaning of the λ parameter of skew–normal and log–skew normal distributions in fluid geochemistry

The literature related to skew–normal distributions has grown rapidly in recent years but at the moment few applications concern the description of natural phenomena with this type of probability models, as well as the interpretation of their parameters. The skew–normal distributions family represents an extension of the normal family to which a parameter (λ) has been added to regulate the skewness. The development of this theoretical field has followed the general tendency in Statistics towards more flexible methods to represent features of the data, as adequately as possible, and to reduce unrealistic assumptions as the normality that underlies most methods of univariate and multivariate analysis. In this paper an investigation on the shape of the frequency distribution of the logratio ln(Cl−/Na+) whose components are related to waters composition for 26 wells, has been performed. Samples have been collected around the active center of Vulcano island (Aeolian archipelago, southern Italy) from 1977 up to now at time intervals of about six months. Data of the logratio have been tentatively modeled by evaluating the performance of the skew–normal model for each well. Values of the λ parameter have been compared by considering temperature and spatial position of the sampling points. Preliminary results indicate that changes in λ values can be related to the nature of environmental processes affecting the data

A prediction model for establishing the disability degree in adults with spinal cord injury: results based on WHO-DAS II perspective

Objective: To establish a prediction model of the degree of disability in adults with Spinal CordInjury (SCI ) based on the use of the WHO-DAS II . Methods: The disability degree was correlatedwith three variable groups: clinical, sociodemographic and those related with rehabilitation services.A model of multiple linear regression was built to predict disability. 45 people with sci exhibitingdiverse etiology, neurological level and completeness participated. Patients were older than 18 andthey had more than a six-month post-injury. The WHO-DAS II and the ASIA impairment scale(AIS ) were used. Results: Variables that evidenced a significant relationship with disability were thefollowing: occupational situation, type of affiliation to the public health care system, injury evolutiontime, neurological level, partial preservation zone, ais motor and sensory scores and number ofclinical complications during the last year. Complications significantly associated to disability werejoint pain, urinary infections, intestinal problems and autonomic disreflexia. None of the variablesrelated to rehabilitation services showed significant association with disability. The disability degreeexhibited significant differences in favor of the groups that received the following services: assistivedevices supply and vocational, job or educational counseling. Conclusions: The best predictiondisability model in adults with sci with more than six months post-injury was built with variablesof injury evolution time, AIS sensory score and injury-related unemployment.

Normal coordinates in the methyl halides

The potential‐energy functions found by Chang for the methyl halides have been put into valence‐type form and revised to eliminate inconsistencies and to accord with the true (nontetrahedral) geometry and the normal frequencies (corrected for Fermi resonance and anharmonicity). The resulting valence‐type force constants and normal coordinates are given for light (CH3) and heavy (CD3) chlorides, bromides, and iodides.

Band gap control via tuning of inversion degree in CdIn2S4 spinel

Based on theoretical arguments we propose a possible route for controlling the band-gap in the promising photovoltaic material CdIn2S4. Our ab initio calculations show that the experimental degree of inversion in this spinel (fraction of tetrahedral sites occupied by In) corresponds approximately to the equilibrium value given by the minimum of the theoretical inversion free energy at a typical synthesis temperature. Modification of this temperature, or of the cooling rate after synthesis, is then expected to change the inversion degree, which in turn sensitively tunes the electronic band-gap of the solid, as shown here by Heyd-Scuseria-Ernzerhof screened hybrid functional calculations.

The determination of all syzygies for the dependent polynomial invariants of the Riemann Tensor. II. mixed invariants of Eeven degree in the Ricci Spinor

We continue our analysis of the polynomial invariants of the Riemann tensor in a four-dimensional Lorentzian space. We concentrate on the mixed invariants of even degree in the Ricci spinor Φ_ABȦḂ and show how, using constructive graph-theoretic methods, arbitrary scalar contractions between copies of the Weyl spinor ψ_ABCD, its conjugate ψ_ȦḂĊḊ and an even number of Ricci spinors can be expressed in terms of paired contractions between these spinors. This leads to an algorithm for the explicit expression of dependent invariants as polynomials of members of the complete set. Finally, we rigorously prove that the complete set as given by Sneddon [J. Math. Phys. 39, 1659-1679 (1998)] for this case is both complete and minimal.

Determination of all syzygies for the dependent polynomial invariants of the Riemann Tensor. III. mixed invariants of arbitrary degree in the Ricci Spinor

In this paper, we rigorously prove that the complete set of Riemann tensor invariants given by Sneddon [J. Math. Phys. 40, 5905 (1999)] is both minimal and complete. Furthermore, we provide a two-stage algorithm for the explicit construction of polynomial syzygies relating any dependent Riemann tensor invariant to members of the complete set.

What (a) difference a degree makes : the evaluation of the new social work degree in England

After many years of debate in the UK about the need for a degree-level qualification in social work, the arguments for a minimum degree-level qualification were accepted. The requirements for the degree in England were developed drawing on work from a number of sources, including a benchmark statement for undergraduate degrees in social work and focus groups with stakeholders. The new degree in England, launched in 2003, involves one extra year’s study; improvements in the qualifying standard for social work; and specific curriculum and entrance requirements. At the time of launching the degree, the government department responsible for funding (Department of Health) commissioned a three-year evaluation of the implementation of the new degree to establish whether the new qualifying level leads to improvements in the qualified workforce. The aim of the evaluation is to describe the experiences of those undertaking the degree, collect the views of the various stakeholders about the effectiveness of the degree and measure the impact of a degree-level qualification on those entering the workforce. This article, written by the team undertaking the evaluation of the England degree, explores the reasons for the methodological approach adopted and the issues that have arisen in setting up the research.

Changes in admissions work arising from the new social work degree in England

The business of admissions to higher education in England is a significant task for academic and support staff. This paper draws on the Evaluation of the New Social Work Degree Qualification in England (2004-2008) to describe the changes in admissions work for social work staff in higher education associated with the change from diploma to a degree level qualification for entry to the profession; to report how staff involved in admissions work are managing these changes; and to identify elements of admissions processes that are perceived to be fulfilling the new requirements of the degree and those which are identified as more problematic. The article draws on two telephone/email surveys of a national sample of social work programmes and on face-to-face in-depth interviews with a sample of teaching staff from nine social work programmes in six higher education institutions undertaken during 2005-2007. The work of admissions staff is rarely scrutinised in studies of higher education or specifically in social work programmes: this article discusses the spectrum of approaches. It recommends monitoring of the outcomes of practices in admissions work that are recasting Department of Health Requirements as the minimum.

Using vignettes to evaluate the outcomes of student learning : data from the evaluation of the new social work degree in England

This paper reports the use of vignettes as a methodology to analyse the extent to which the new social work degree programmes enabled students to develop their analytical and reflective capabilities. Two vignettes, which focused on children and families and adult social care respectively, were developed for the study. Students were asked to respond in writing, from the perspective of a social worker, to a standard set of questions at the beginning (T1) and end of their degree programme (T2). Considering the responses to all questions across the two vignettes, a series of scales was developed to measure the key themes which had been identified by qualitative analysis. These included ‘Attention to process of relationships’ and ‘Social/structural/political awareness’. Responses were also rated as ‘descriptive’, ‘analytic’ or ‘reflective’.

Students from six universities in England participated. From an original sample of 222 students, it was possible to match 79 T1 and T2 responses. Analysis of variance demonstrated statistically significant increases in nine of the 11 themes and increases in ratings for analysis and reflection.

In conclusion, vignettes can be used to produce both qualitative and quantitative data in respect of changes in students’ acquisition of knowledge and skills over time.

Growth of the speckled swimming crab, Arenaeus cribrarius (Lamarck, 1818) (Crustacea, Brachyura, Portunidae), in Ubatuba (SP), Brazil

A total of 2629 individuals of Arenaeus cribrarius (1293 males and 1336 females) were captured in Ubatuba (SP), from August 1996 to July 1997. Individuals were distributed in 5 mm size class carapace width (CW), to verify sex-specific growth-age equations. The Von Bertalanffy model was chosen to determine the growth rate and expressed by CW=120.52[1-e(-1.80t)] for males and CW=100.81[1-e(-1.60t)] for females. The age estimated for the first juvenile stage (t(o)) was 6.1 and 8.3 days for males and females, respectively. The maximum age determined was 1.8 years for males and 2 years for females, which correspond to a maximum size of 115.8 and 96.7 mm, respectively. The maximum size (CWmax) estimated using 95% of asymptotic size was 114.5 mm for males and 95.8 mm for females. Males have a precocious sexual maturity (5 months) when compared to females (6.8 months). The growth rate and size of A. cribrarius are higher than other portunid species, with great interest for aquaculture.

Detection of hemoplasma and Bartonella species and co-infection with retroviruses in cats subjected to a spaying/neutering program in Jaboticabal, SP, Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)